But, well, I didn't understand your answer; I don't see where it fits my questions, it doesn't make any sense, as it doesn't answer ANY of my questions.

ALL ecchi and harem animes - all of them, no exceptions - do that thing of making many or most male characters with dark skin, but they don't make ANY female character with dark skin, none whatsoever! ALL white!

What I REAAAALLY would like to ask ANY - at least one! - of the creators/producers/artists of these kinds of anime is simply: "Why are there so many male characters with dark skin and not a single female character with dark skin??"

But if I had the opportunity to ask more, or elaborate more, that question could be separated into:

1) Why many or most male characters have dark skin when it doesn't represent most Japanese man?
2) Why are all the women and girls white if there are so many male characters with dark skin?
3) Why aren't the male characters as white as the girls?
4) Or why don't make a few female characters with dark skin as well? Not a single one?

But I'm almost sure I know the reason. But I would really like to have the opportunity to ask that to any creator/producer/artist of these kinds of anime to know what they'd have to say. An actual, proper answer, not an elusive, short, senseless excuse (please, I'm not talking about your answer).

You partially guessed the reason for them doing that (in every erotic/pornographic Japanese-style media, and also in ecchi/harem anime). But as the saying goes in my country, "the hole is much deeper".

Years ago, when I was still starting to get into ecchi/harem animes and eroges, and didn't know Pixiv and Yande.re yet, I didn't pay attention to that. But as I started watching more and more ecchi and harem animes, discovering more eroges, doujinshi, and discovering Pixiv and Yande.re and having access to much more hentai and such illustrations that I'd never had before (in the amount/frequency that I do now), I started to notice that a lot, and it started to bother me. Specially after I learned some things:

A couple years ago I watched a video on YouTube of a very charismatic and funny Chinese man that has been living in my country, Brazil, for a few years now, and he learned and speaks my language well. On his channel he talks about life in China Vs. in Brazil, costumes in both countries, and things and peculiarities about China and my country. And the subject of this particular video was "beauty standards in China Vs. in the West". One of the beauty standards in China that he mentioned was white skin, the whiter, the more beautiful it is. The beauty standards in China are pretty much the same in Japan and Korea as well. So, after that, I started to think... "If they find white skin more beautiful, the whiter, the more beautiful it is, then what about the contrary? The darker, less white would be less beautiful or ugly/uglier? Isn't that kinda racist? Or could lead to racism?

Some time after that I saw an illustration on Yande.re of a foursome (two guys with two girls). The girls were very beautifully drawn, and they were very beautiful as well; but the guys... they were horrendous! And very badly drawn. The drawing of the guys and the drawing of the girls didn't even appear to have been made by the same artist, the so much different in quality and beauty that they were! I posted a comment asking why would the artist do that and ruin such a beautiful picture with guys so horrendous and badly drawn, making such a contrast with the beautiful and beautifully drawn girls, mentioning that the guys and the girls didn't even appear to have been drawn by the same artist. One guy answered me saying that the Asian men liked that in such illustrations, they like to see ugly guys fucking beautiful girls, because many of these men find themselves ugly as well, so they think, "If that(those) ugly guy(s) can pick up and have sex with such beautiful girls, then I can too!" He gave other explanations as well for the ugly and badly drawn guys in the picture, but that first explanation was that intrigued me the most, as it's totally contrary to what I think. I think that those horrendous and badly drawn guys ruin a beautiful picture and make it less pleasant to look at. Also when I see a guy(s) fucking a girl(s), I like to imagine myself there in his(their) place, and I don't want to be represented/be compared to an horrendous guy! I prefer much more to be compared/be represented by a fine or normal looking man.

So, you just make the math:

1) They think that white/whiter = beautiful/more beautiful;
2) so, by that, you assume that they think that dark/darker skin = ugly/uglier/less attractive;
3) Asian men like to see ugly/horrendous guys in sexual interactions/intercourse with girls;
4) almost all erotic/pornographic Japanese-style illustrations and doujinshi, eroges, etc. feature dark-skinned men copulating with white girls. Saving some exceptions (like the one here in this post), the girls are always white and the guys are always dark-skinned, or have a darker skin than the girl(s), or, as I mentioned before, have unrealistic dark skin tones, like clay, rock, or something worse.

So you just add 1+1 and you now reach the conclusion why most erotic/pornographic Japanese-style illustrations, doujinshi, eroges, etc. feature dark-skinned men copulating with white girls. And, for the same reason, why ALL ecchi/harem animes feature dozens, hundreds, of dark-skinned male characters while ALL the girls are ALWAYS white! Even if it's unrealistic, ridiculous and impossible anywhere in the world!

That conclusion is even more reinforced by reports I've read of immigrants in Japan that constantly suffer or have suffered racism or xenophobia there, specially dark-skinned immigrants, specially from SE Asian countries like the Philippines.

You see now what annoys me so much? I abominate racism, and I will never tolerate that!
Do you understand now why I said in the beginning that it always annoyed me, but I was always afraid to talk about that? Because of that subject. It's sad. But for years I always wanted to talk about it with someone, somewhere, but never had the opportunity, and I was always afraid.

As I said before, the matter of lack of dark-skinned female characters in ecchi and harem shows alone is not really what bothers or annoys me (although I do miss it and would like it). I would have never complained about that or got annoyed about that if the male characters in these shows were also all white like the women. The problem, what really annoys me, is them making dozens, hundreds of dark-skinned male characters in these kinds of anime (often the majority of them) while all the girls, all the women being white - even if it's an absurd, impossible thing anywhere in the world -, and the reason for that. :(

I'm always perplexed that they still do that in these animes, even in the 21st century, even in the 2020's, specially considering that anime is such a popular media worldwide, even in the West! How come no-one else sees what I see and is bothered, annoyed by that? How come no-one else complains and speaks up against it? Specially Westerners. Specially those SJW Westerners that like to speak up against fictional underage characters in erotic/pornographic Japanese illustrations and the like, and I don't even mind that; I even like a few loli pictures, but racism is something I will never accept and will never tolerate!

Why can't they make a few dark-skinned girls in these shows? Why never one or two at least? There are so many beautiful dark-skinned girls in other kinds of anime or anime-style games, like Nessa, in Pokémon, Dehya and the others in Genshin Impact; Coconut is one of the most popular girls in NEKOPARA. Heck, Nagatoro is so popular now, and she is so cute, even if she is not naturally dark-skinned...

Well, anyway, I love all kinds of Japanese-style erotic/pornographic illustrative content and I also love ecchi and harem anime, and I always will, even with that problem. I'd just like that they stopped doing that. :(

So sorry for another wall of text (if you have read this far). But I think I've said everything that I wanted (that was stuck in chest for so long and I wanted to speak about it with someone, somewhere), so (hopefully) there isn't going be another one.

Brazil is also one of the most diverse countries in the world, even more than France; I dare say possibly the most one. It started with the South-American natives, the Indians, that exist until today; then the Portuguese came in 1500; then the African slaves (MANY of them!). Still during the slavery, Brazil received a huge influx of German immigrants in the South (even today most of the population in the two Southern-most states are German descendants). After the abolition of slavery in 1888, Brazil needed a huge (salaried) manpower to work in the plantations to replace the slaves; most of that manpower was filled by many Italian immigrants. Some time after the Italians, we started receiving MANY Japanese immigrants too that were mostly established in the state of São Paulo (that's why today in its homonymous capital there is the biggest Japanese town outside of Japan - the neighborhood know as 'Liberdade'). After the German, Italian, and Japanese immigrants, we received Finnish immigrants; Arabic as well; and many others from all Europe. At some point we also started receiving MANY, like really MANY Chinese immigrants! Most of them open their own businesses with electronic shops or snack bars. :P There are also immigrants from Haiti, Venezuela, Peru and many other Latin-American countries. They say that New York is the "Big Apple", but Brazil is really a huge basket of them! LOL! Everyone is welcome here and treated as Brazilians, as brothers and sisters; every immigrant feel at home here; there's no prejudice against them like there is in Japan and some in the US. That's what I love and one of things I find most beautiful about Brazil and its people. ^^

Because of the big amount of slaves that were brought to Brazil in the past, people of color (dark-skinned) represent the majority of the population in Brazil today (9.1% of self-declared black and 47% of self-declared 'pardos' (mixed of white and black people)); white people are 43% of the population, as per the 2021 census. Because of the large amount of people of color and the miscegenation in Brazil, we don't make segregation and distinction of races here in the everyday life (not even in the penitentiaries, like they do in the US). I will not say that there isn't racism, of course there are isolated cases, as there is everywhere, but black (I suspect it's even more than 9.1%) and pardo people are so common here, as well as mixed couples, that we simply don't make distinctions.

I think whenever and wherever there are more diversity and miscegenation, the less racism there is; and, on the contrary, the less diversity and miscegenation, the more ignorance and racism there is. There's very little diversity and miscegenation in Japan, hence the big racism and xenophobia there. But I think more and more there are less racist Japanese people; the movie 'A Silent Voice' (Koe no Katachi) is a good example. Yet they still do that racist cliché in erotic/pornographic illustrations and in ecchi/harem anime, even in the 21st century and the 2020's. But I hope it changes over time, with the new generations that are more and more aware and globalized.